This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A050170 #24 Jan 09 2024 16:12:33
%S A050170 1,2,4,8,3,6,13,5,11,24,10,22,9,20,44,19,42,18,40,17,7,15,33,14,31,69,
%T A050170 30,67,29,12,26,58,25,55,122,54,120,53,23,51,114,50,111,49,21,46,102,
%U A050170 45,100,223,99,221,98,43,96,214,95,212,94,210
%N A050170 a(1) = 1, a(n) = floor(a(n-1)/sqrt(5)) if this is not among 0,a(1),...,a(n-1); otherwise a(n) = floor(a(n-1)*sqrt(5)).
%C A050170 Does every positive integer occur exactly once?
%C A050170 Records occur at indices 1, 2, 3, 4, 7, 10, 15, 26, 35, 50, 87, 124, 179, 306, ... with corresponding values 1, 2, 4, 8, 13, 24, 44, 69, 122, 223, 348, 614, 1118, 1744, .... - _Peter Kagey_, Jan 24 2018
%H A050170 Ivan Neretin, <a href="/A050170/b050170.txt">Table of n, a(n) for n = 1..10000</a>
%t A050170 a[1] = 1; a[n_] := a[n] = If[FreeQ[Join[{0}, Array[a, n-1]], f = Floor[a[n-1]/Sqrt[5]]], f, Floor[a[n-1]*Sqrt[5]]]; Array[a, 60] (* _Jean-François Alcover_, Sep 12 2017 *)
%K A050170 nonn,look
%O A050170 1,2
%A A050170 _Clark Kimberling_